This invention relates generally to intraocular lens implantation, and more particularly concerns apparatus and method for achieving such implantation via a very small surgical incision in the corneo-scleral limbus of the eye.
In the past, forceps have been used with blades that clamp the plastic lens for introducing it into the eye via a relatively wide wound or incision in the corneo-scleral limbus. A typical wound was required to have a width of about 7-15 millimeters in order to pass the forcep blades and to allow spreading of the blades to release the plastic lens in the eye.
Problems encountered included laceration of the elastic silicon lens, and undesirable sudden release and rapid unfolding of the lens (as opposed to gentle release) causing injury to intraocular tissue, due to inability to separate the blades widely and gently. The usual wide incision is undesirable due to the amount of suturing required to close the wound, and time required for such suturing, increased or undesirably long convalescence time, increase in astigmatic complications, difficulty in preventing collapse of the intraocular chambers during the operation, and increased risk of post-operative complications. Further, plastic lenses could and did at times become captured by the blades of prior forceps, requiring dangerous instrumentation to release the lens from the grasp of such forceps. The invention of U.S. Pat. No. 4,513,957 represents one approach to the solution of this problem.
Additionally, one of the most significant advances in the surgical procedure of phoco-emulsification which has now become foremost for high volume eye surgeons is that of cracking the extra hard brittle central nuclear lens mass into smaller more readily manageable pieces. This has been particularly difficult, and has forced fine surgeons to abandon phoco-emulsification as their standard procedure for the extraction of a cataract.
Also, there is need for an instrument capable of dilating the eye pupil, as during a cataract operation.